During 1992 and 1993 a total of 298 S1 lines of maize (245 obtained from improved varieties and 53 from Colombian landraces) were evaluated for grain yield and 12 other characteristics, including nitrogen (N) use efficiency. The objective was to identify the best lines and to integrate these with existing germplasm in an improvement program to obtain genotypes with high yield potential and good agronomic performance under conditions of high and low N availability. Evaluations were conducted at the National Research Center, Turipana', of the Colombian Agricultural Institute (ICA) (9°N, 76° W, 13 m elevation, average temperature 28 °C, 1076 mm annual rainfall, and 83% RH). The experimental design was a randomized complete block. The interaction of genotype (line) and environment (levels of N) was not significant for the variables of major agronomic interest, i.e., grain yield, length and diameter of the ear, shelling percent, harvest index and days to silking and anthesis. From the individual and combined analyses it can be inferred that the improved materials and the Colombian landrace populations that were evaluated can both supply good lines for an improvement program in normal conditions of nitrogen fertilization, under conditions of nitrogen stress and simultaneously for both environments. A total of 25 superior white and 25 superior yellow lines were identified and recombined by color to create two base populations for recurrent selection under normal conditions and under conditions of nitrogen stress.

Spanish

9802|AGRIS 9702

Jose Juan Caballero

CIMMYT Publications Collection